Food and water interrelations and the protein requirement for growth of an altricial bird, the cockatiel (Nymphicus hollandicus).

Cockatiel (Nymphicus hollandicus) chicks were hand-fed diets diluted to various levels of solids to determine the optimum ratio of solids to water for survival and growth. In later experiments protein levels in the solid portion of the diet were varied to determine the protein requirement for growth. Cockatiels survived and grew well when hand-fed a diet of 7% solids during the first 4 d after hatching, followed by 30% solids until 28 d of age. The solid portion of this diet contained 20% isolated soybean protein, methionine, cornstarch, vitamins and minerals. When chicks were fed 10% solids from hatch, growth rates were one-third to one-half those of chicks fed 20 or 30% solids; by 23 d most chicks fed 10% solids had died, with survivors being permanently stunted. By 3-5 d before death, crop emptying ceased, yet chicks appeared hungry. Chicks fed 20 or 30% solids from hatching grew well after an initial 3-d period of some mortality. The water needed by cockatiel chicks decreased during the first 4 d posthatching; thereafter, diets containing 90% water or more were harmful. Groups of chicks fed diets ranging from 5 to 35% protein of the solids exhibited wide differences in growth, with 20% protein being the lowest level that permitted maximal growth.